add getLatestBlockhash and deprecate getRecentBlockhash

Author: wiyarmir

solana-kotlin/src/commonMain/kotlin/net/avianlabs/solana/methods/getLatestBlockhash.kt

@@ -0,0 +1,36 @@
+package net.avianlabs.solana.methods
+
+import kotlinx.serialization.Serializable
+import kotlinx.serialization.json.addJsonObject
+import kotlinx.serialization.json.buildJsonArray
+import kotlinx.serialization.json.put
+import net.avianlabs.solana.SolanaClient
+import net.avianlabs.solana.client.RpcResponse
+import net.avianlabs.solana.domain.core.Commitment
+
+/**
+ * Returns the latest blockhash
+ *
+ * @param commitment Optional [Commitment] level
+ */
+public suspend fun SolanaClient.getLatestBlockhash(
+  commitment: Commitment? = null,
+): LatestBlockHash {
+  val result = invoke<RpcResponse.RPC<LatestBlockHash>>(
+    method = "getLatestBlockhash",
+    params = buildJsonArray {
+      commitment?.let {
+        addJsonObject {
+          put("commitment", it.value)
+        }
+      }
+    }
+  )
+  return result!!.value!!
+}
+
+@Serializable
+public data class LatestBlockHash(
+  val blockhash: String,
+  val lastValidBlockHeight: Long,
+)

solana-kotlin/src/commonMain/kotlin/net/avianlabs/solana/methods/getRecentBlockhash.kt

@@ -13,7 +13,14 @@ import net.avianlabs.solana.domain.core.FeeCalculator
  * Returns the latest blockhash
  *
  * @param commitment Optional [Commitment] level
+ *
+ * @deprecated Use [getLatestBlockhash] instead
  */
+@Deprecated(
+  "No longer a part of solana-core after 2.0. Use getLatestBlockhash instead",
+  ReplaceWith("getLatestBlockhash"),
+  DeprecationLevel.ERROR,
+)
 public suspend fun SolanaClient.getRecentBlockhash(
   commitment: Commitment? = null,
 ): RecentBlockHash {

solana-kotlin/src/commonTest/kotlin/net/avianlabs/solana/domain/program/SystemProgramTest.kt

@@ -34,7 +34,7 @@ class SystemProgramTest {
 
     val rentExempt = client.getMinimumBalanceForRentExemption(SystemProgram.NONCE_ACCOUNT_LENGTH)
 
-    val blockhash = client.getRecentBlockhash()
+    val blockhash = client.getLatestBlockhash()
 
     val initTransaction = Transaction()
       .addInstruction(